diff --git a/include/Makefile b/include/Makefile
index b80d23585..782ded77e 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -15,6 +15,7 @@ INCS+=	minix/a.out.h minix/bitmap.h minix/callnr.h minix/cdrom.h \
 	minix/com.h minix/config.h minix/const.h minix/cpufeature.h \
 	minix/crtso.h minix/debug.h minix/devio.h minix/dirent.h \
 	minix/dir.h minix/dl_eth.h minix/dmap.h minix/driver.h \
+	minix/limits.h \
 	minix/drivers.h minix/drvlib.h minix/ds.h minix/endpoint.h \
 	minix/fslib.h minix/ioctl.h minix/ipc.h minix/ipcconst.h \
 	minix/keymap.h minix/minlib.h minix/mq.h \
diff --git a/include/limits.h b/include/limits.h
index 3baa81d0e..d2742005e 100644
--- a/include/limits.h
+++ b/include/limits.h
@@ -6,6 +6,8 @@
 #ifndef _LIMITS_H
 #define _LIMITS_H
 
+#include <minix/limits.h>
+
 /* Definitions about chars (8 bits in MINIX, and signed). */
 #define CHAR_BIT           8	/* # bits in a char */
 #define CHAR_MIN        -128	/* minimum value of a char */
@@ -62,8 +64,13 @@
 #define _POSIX_MAX_INPUT   255	/* you can type 255 chars ahead */
 #define _POSIX_NAME_MAX DIRSIZ	/* max. file name length */
 #define _POSIX_NGROUPS_MAX   8	/* max. number of supplemental groups */
-#define _POSIX_OPEN_MAX     16	/* a process may have 16 files open */
-#define _POSIX_PATH_MAX    255	/* a pathname may contain 255 chars */
+
+/* a process may have this many files open */
+#define _POSIX_OPEN_MAX  __MINIX_OPEN_MAX
+
+/* a pathname may contain at most this many chars */
+#define _POSIX_PATH_MAX    __MINIX_PATH_MAX
+
 #define _POSIX_PIPE_BUF    512	/* pipes writes of 512 bytes must be atomic */
 #define _POSIX_STREAM_MAX    8	/* at least 8 FILEs can be open at once */
 #define _POSIX_TZNAME_MAX    3	/* time zone names can be at least 3 chars */
@@ -85,7 +92,7 @@
 #define ARG_MAX           4096	/* args + environ on small machines */
 #endif
 #define CHILD_MAX    _NO_LIMIT	/* MINIX does not limit children */
-#define OPEN_MAX            30	/* # open files a process may have */
+#define OPEN_MAX  __MINIX_OPEN_MAX	/* # open files a process may have */
 #if 0			/* V1 file system */
 #define LINK_MAX      CHAR_MAX	/* # links a file may have */
 #else			/* V2 or better file system */
@@ -94,7 +101,7 @@
 #define MAX_CANON          255	/* size of the canonical input queue */
 #define MAX_INPUT          255	/* size of the type-ahead buffer */
 #define NAME_MAX        DIRSIZ	/* # chars in a file name */
-#define PATH_MAX           255	/* # chars in a path name */
+#define PATH_MAX  __MINIX_PATH_MAX	/* # chars in a path name */
 #define PIPE_BUF          7168	/* # bytes in atomic write to a pipe */
 #define STREAM_MAX          20	/* must be the same as FOPEN_MAX in stdio.h */
 #define TZNAME_MAX           3	/* maximum bytes in a time zone name is 3 */
diff --git a/include/minix/limits.h b/include/minix/limits.h
new file mode 100644
index 000000000..41dcc4455
--- /dev/null
+++ b/include/minix/limits.h
@@ -0,0 +1,12 @@
+/* The <minix/limits.h> header defines the Minix values for some MINIX
+ * constants. Both the MINIX constants and the non-posix constants
+ * refer to these underlying definitions.
+ */
+
+#ifndef _MINIX_LIMITS_H
+#define _MINIX_LIMITS_H
+
+#define __MINIX_OPEN_MAX     30	/* a process may have 30 files open */
+#define __MINIX_PATH_MAX    255	/* a pathname may contain 255 chars */
+
+#endif /* _MINIX_LIMITS_H */
diff --git a/include/sys/param.h b/include/sys/param.h
index 389a078e2..13b2c6bc8 100644
--- a/include/sys/param.h
+++ b/include/sys/param.h
@@ -6,9 +6,10 @@ sys/param.h
 #define __SYS_PARAM_H__
 
 #include <limits.h>
+#include <minix/limits.h>
 
 #define MAXHOSTNAMELEN  256	/* max hostname size */
 #define NGROUPS		8	/* max number of supplementary groups */
-#define MAXPATHLEN	PATH_MAX
+#define MAXPATHLEN	__MINIX_PATH_MAX
 
 #endif /* __SYS_PARAM_H__ */
diff --git a/include/sys/select.h b/include/sys/select.h
index 3132d718f..8b7f3b23b 100644
--- a/include/sys/select.h
+++ b/include/sys/select.h
@@ -1,12 +1,9 @@
 #ifndef _SYS_SELECT_H
 #define _SYS_SELECT_H 1
 
-#ifndef _POSIX_SOURCE
-#define _POSIX_SOURCE 1
-#endif
-
 #include <sys/time.h>
 #include <minix/types.h>
+#include <minix/limits.h>
 #include <limits.h>
 #include <string.h>
 
@@ -22,7 +19,7 @@ typedef u32_t fd_mask;
 
 /* Default FD_SETSIZE is OPEN_MAX. */
 #ifndef FD_SETSIZE
-#define FD_SETSIZE		OPEN_MAX
+#define FD_SETSIZE		__MINIX_OPEN_MAX
 #endif
 
 /* We want to store FD_SETSIZE bits. */